Response of Saccharomyces cerevisiae to change in oxygen provision

Oxygen is a major determinant of cellular physiology and is of particular importance in industrial processes, in which the cost of oxygen supply must be balanced with performance requirements. Bakers' yeast, Saccharomyces cerevisiae, is one of the most exploited industrial organisms and regardless of whether the process is aerated or non-aerated, the role of oxygen is crucial. In order to understand the response of S. cerevisiae to oxygen, we determined the physiological state of CEN.PK113-1A cells in terms of 17 metabolites and 69 genes related to central carbon metabolism in glucose-limited chemostat cultivations with various concentrations of provided oxygen. After assessing the steady states, anaerobic conditions were imposed in the same cultures to determine how the cells achieved their new, anaerobic steady state. The concentration of TCA cycle metabolites and all glycolytic metabolites except 2- and 3-phosphoglycerate and phosphoenol pyruvate was higher in anaerobic than in fully aerobic conditions. Provision of only 0.5 to 1% O2 reduced the concentration of most metabolites, compared with anaerobic conditions. Transcription of most genes analysed was reduced in conditions of low (compared with high) O2 availability. To extend the analysis to whole genome we additionally generated data sets of transcriptional profiling and total proteomics. These data sets will give us knowledge on how the whole metabolism of the cell changes when the external oxygen conditions change.